1. Field of the Invention
The present invention relates to a vehicle position recognizing system in which a predetermined magnetic field is formed on a predetermined traffic lane, and a vehicle running on the traffic lane detects the position of the own vehicle with a high accuracy.
2. Description of the Prior Art
As shown in, for example, Japanese Iatent Laid-Open No. 10-206173 specification, the conventional vehicle position recognizing system comprises: one or more of magnetic field forming means that is laid on the road surface at a predetermined position to form a predetermined magnetic field; magnetic field intensity detecting means for detecting the magnetic field formed by the magnetic field forming means; vehicle position operation suitability judging means for judging the suitability of performing the vehicle position operation by using the magnetic field intensity obtained by the magnetic field intensity detecting means; and vehicle position operating means that receives the judgment result of the vehicle position operation suitability judging means, and detects the vehicle position on the basis of the magnetic field intensity detected by the magnetic field intensity detecting means.
Furthermore, the magnetic field intensity detecting means is arranged such that it judges in advance the position where the effect of the magnetic field forming means is not received (for example, the middle point of the magnetic field forming means) by using non-magnetic field position judging means, and it records the magnetic field intensity of the non-magnetic field position, and it corrects the magnetic field intensity obtained by the magnetic field intensity detecting means.
With such a configuration, in the conventional system, the magnetic field intensity can be determined without receiving the effect of the earth magnetism or the magnetization of the vehicle, and therefore, an accurate vehicle position can be obtained.
However, the above described conventional system has such a problem that the magnetic field is wrongly detected, or it is not detected, or the vehicle horizontal position with a large error is outputted in the case where a material, a magnetic body or the like which powerfully disturbs the magnetic field exists on the traffic lane, especially, in the case where the magnetized metal in the joint of a concrete road or the structural body in a tunnel or the like forms a magnetic field larger than that of the magnetic field forming mean such as a magnetic marker.
The present invention is made for solving the above described problems, and it is an object to provide a vehicle position recognizing system by which it is possible to eliminate the effect of the magnetic disturbance of a material, a magnetic body or the like which disturbs the magnetic field on the traffic lane, and to surely detect the magnetic marker, and to accurately find the horizontal position of a vehicle.
The vehicle position recognizing system according to the invention of claim 1 is a system comprising: at least one signal area forming means for forming a magnetic field at a predetermined position on the road surface; at least one magnetic field intensity detecting means for detecting intensity of magnetic field formed by the above described signal area forming means; and vehicle position operating means for performing operation of a vehicle position on the basis of magnetic field intensity obtained by the above described magnetic field intensity detecting means at points separated forward and backward from the above described signal area forming means by a predetermined amount.
According to this configuration, there is such an effect that it is possible to eliminate the effect of the magnetic disturbance of a material, a magnetic body or the like which disturbs the magnetic field on the traffic lane, and to surely detect the magnetic marker, and to accurately determine the horizontal position of the vehicle.
The vehicle position recognizing system according to the invention of claim 2 is a system in which the above described vehicle position operating means has correcting means for correcting magnetic field intensity of the above described signal area forming means on the basis of magnetic field intensity obtained from the above described magnetic field intensity detecting means at points separated forward and backward from the above described signal area forming means by a predetermined amount.
According to this configuration, there is such an effect that even in an extremely large magnetic disturbance, the effect thereof can be eliminated, and an accurate vehicle position can be obtained, and furthermore, even in the case of the first signal area forming means, an accurate vehicle position can be obtained, and furthermore, it is also possible to simultaneously perform elimination of the effect to the magnetic field intensity detecting means because of the temperature fluctuation of the magnetic field intensity detecting means or the sudden magnetization of the vehicle body by the signal area forming means or the like, and moreover, even if the intervals of laying of the magnetic field forming means are variously changed, the detecting reliability is high and the detection accuracy of the vehicle position is also high.
The vehicle position recognizing system according to the invention of claim 3 is a system in which the above described vehicle position operating means has judging means for judging presence of the above described signal area forming mean on the basis of magnetic field intensity obtained from the above described magnetic field intensity detecting means at points separated forward and backward from the above described signal area forming means by a predetermined amount.
According to this configuration, there is such an effect that even in an extremely large magnetic disturbance, the effect thereof can be eliminated, and the detecting reliability can be improved, and furthermore, even in the case of the first signal area forming means, the detecting reliability can also be improved.
The vehicle position recognizing system according to the invention of claim 4 is a system in which the above described correcting means corrects magnetic field intensity of the above described signal area forming means on the basis of an average value of magnetic field intensity obtained from the above described magnetic field intensity detecting means.
According to this configuration, there is such an effect that even in an extremely large magnetic disturbance, the effect thereof can be eliminated, and furthermore, an accurate vehicle position can be obtained, and furthermore, even in the case of the first signal area firming means, an accurate vehicle position can be obtained, and furthermore, it is also possible to simultaneously perform the elimination of the effect to the magnetic field intensity detecting means because of the temperature fluctuation of the magnetic field intensity detecting means or the sudden magnetization of the vehicle body by the signal area forming means or the like, and moreover, even if the intervals of laying of the magnetic field forming means are variously changed, the detecting reliability is high and the detecting accuracy of the vehicle position is also high.
The vehicle position recognizing system according to the invention of claim 5 is a system in which the above described judging means judges presence of the above described signal area forming means on the basis of an average value of magnetic field intensity obtained from the above described magnetic field intensity detecting means.
According to this configuration, there is such an effect that even in an extremely large magnetic disturbance, the effect thereof can be eliminated, and the detecting reliability can be improved, and furthermore, even in the case of the first signal area forming means, the detecting reliability can be improved.